Intensively bred pigs are very prone to disease which affects their growth rate and consequently the profits available from a pig=rearing establishment. One important factor in the propensity of piglets to suffer from disease is the stress factor. Immediately after birth piglets are highly stressed and lose temperature rapidly in traditional conditions. Consequently, piglets under shock are extremely prone to disorders of the bodily functions especially the lungs. This is particularly noticeable at birth since the animals lungs are undergoing a major change at birth from being rudimentary organs fed from the blood supply in the placenta to independent organs constituting the primary oxygenation source for the blood. Lung infections such as pleurisy and pneumonia lead to a high mortality rate which matches that from crushing. British Pat. No 2,121,665 describes apparatus for confining a sow during farrowing, comprising a pen in the form of an elongate open framework of bars the spacing of which is such as to contain a sow and prevent her from turning around, and a piglet confinement chamber at one end of the framework, the said framework incorporating a frame panel on a major side thereof, which panel can be opened to allow the sow to turn around.
The term "sow" as used in this specification will be understood to include all female pigs capable of producing a litter of piglets, and including the so-called "gilts" namely partly mature female pigs prior to the delivery of the first litter.